1. Field of the Invention
The present invention relates to an indentation tester.
2. Description of Related Art
Conventionally, a material tester is known in which an indentation tester forms an indentation by pressing an indenter column into a surface of a sample, the indenter column having an indenter on a foremost end thereof. The indentation tester then measures a depth of the indentation (displacement amount of the indenter) with a displacement gauge. Using a relationship between the displacement amount and a load placed on the indenter, the indentation tester measures values for physical characteristics of the sample, such as hardness. (See, for example, Japanese Patent Laid-open Publication No. 2009-156688.) Using the above-described indentation tester, a material testing method (instrumented indentation test) evaluates the indentation depth of a nanoindentation made by the indenter, for example. In this material testing method, in order to eliminate effects from elastic deformation of an indentation tester device body or sample holder, a measurement method using the sample surface as a baseline for the measurement of the indentation depth is effective.
However, due to the extremely high sensitivity of the device measuring the indentation depth, there is an exceptionally small margin for a baseline position. Simply by mounting a new indenter to the indenter column, a height of the indenter may vary due to individual differences in each indenter, leading to positioning drift in a vertical direction. Thus, when the indentation test is performed after switching indenters, there is a risk that measurement of a maximum indentation depth may not be performed to satisfaction or that resolution may be reduced. Therefore, in order that an indenter coupling (coupled to the indenter) is positioned at the vertical-direction baseline position for an indenter position detector (which measures the indentation depth) when the indenter reaches the sample surface, a mounting surface on the indenter or a contactor must be readjusted or a spacer must be inserted when switching indenters. The operation of switching indenters thus requires time and may also increase costs.